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Heating, Air Conditioning, Fridge, HVAC/Air handler motor is noisy after replacing run cap


My air handler motor stopped working at home. I called a tech who suspected that run capacitor got bad and so he replaced it. For first 6 hours, it seemed to run fine although with some noise however later the noise level increased and I noticed that at times, motor was not running as if not enough torque. I then called York to get specs of capacitor originally on the unit (my tech took away the old part with him) and was told that it was 7.5 microfarad. What I have now is 6 microfarad one which also has a 100K resistor mounted in parallel (which was not there on my old one as I recall).

Does the problem I have is because of motor itself or lower microfarad rating capacitor and/or 100K resistor mounted in parallel with the capacitor?

i will greatly appreciate a response.

I do not see bleed resistors on run caps very often, if ever.  The bleed resistors are found on start caps almost all of the time.  The resistor has no affect on the motor, but the MFD rating does.  The rating needs to be matched to the installed motor.  If the motor is not the orig. motor, then the rating given to you by the factory might be wrong.  The nameplate on the motor should have the MFD rating.  It is quite possible the motor is on its way to failure, which is why the run cap went bad.  It is also possible the bad run cap has caused the motor to fail. Using the wrong MFD rating can cause the motor to fail as well.


Heating, Air Conditioning, Fridge, HVAC

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Craig HVAC Expert


I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.


I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

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